The INFP suicide thread got me thinking. In that I mentioned the last time I thought about it, which is also the most seriously I've thought about it (ignoring the long period as a teenager that I can't remember very well) and the closest I've come. But the truth is it's not unusual for me. While in general I'm fairly happy, I frequently (at least once every two months) get short, sharp bouts of depression, lasting no longer than four days, in which I will usually become pre-occupied with thoughts of death and other bad ideas, like moving out on to the streets or a homeless shelter, before gradually feeling better over the course of a day or two. These are worrying because they don't seem to be triggered by anything obvious, but they are made more severe by things in my life suggesting hopelessness, and if my personal circumstances become truly hopeless they might well provide that extra push.
So I'm wondering three things: how common is this particular pattern, has anyone had any luck overcoming it or understanding it, and might it be related to type? I wonder if dom-Fi leads to more time spent ruminating over negative feelings and not being able to leave them alone and distract yourself when they come, and if there's anything I can do to help that, or if it's entirely unrelated. In some ways I would expect Fi to be an advantage, because I do find in particular contexts I'm good at manipulating my own feelings, for example when I notice that they conflict with an ethical principle of mine or that I reach. Other people say they can't do that, if they know a feeling doesn't make sense they just accept that they've developed feelings inconsistent with their logical conclusions. I've generally imagined it to be an Fi skill to allign the two when necessary. So why do I slip so quickly from a fixation on subjects of morbid fascination (which is how it starts - I don't know if it's the trigger, or just the first sign of what's happening, as with epileptic aurae, but it's irresistable because and I can't feel much of any feeling unless it's involved, and the brain naturally seeks sufficient stimulation from wherever it can get it) into despair? Some people stay clinically depressed for months before becoming suicidal, and I don't see how they can last so long!
I've never kept a record to find out just how regularly this happens, which perhaps would be a good idea, because if it is chronologically predictable it would seem less likely to be triggered by some aspect of my mind and more likely a biological thing.